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Biomedical subjects

A R Laddu

Publications and source records attributed to A R Laddu.

At least 37 records · Page 2Linked to original sources
PubMed1982

Acebutolol therapy for ventricular arrhythmia. A randomized placebo-controlled double-blind multicenter study.

The safety and efficacy of acebutolol in suppressing ventricular ectopy was evaluated in 60 males (average 59 years) using 24-hour Holter recordings and a double-blind, randomized, crossover protocol. Acebutolol, 200 mg and 400 mg thrice daily, was compared with placebo. Only patients who had a mean of at least 30 ventricular premature complexes (VPCs) per hour on three 24-hour control Holter recordings were included. Analysis of Holter recordings revealed greater than 70% reduction in VPCs/hour from control levels during acebutolol therapy in over 50% of the 60 patients; dose-related reduction in the mean number of single and paired VPCs and ventricular tachycardia episodes (p less than 0.05) by acebutolol; and significant, asymptomatic reduction in resting heart rate and blood pressure. All side effects were transient. Acebutolol was discontinued because of side effects in one patient only.

Acebutolol↗
PubMed1982

Pulmonary effects of acebutolol, a "cardioselective" beta adrenergic blocking agent.

The effect of chronic oral therapy with acebutolol, a cardioselective beta adrenergic blocking agent, was evaluated on resting pulmonary functions in a group of patients who were free of overt obstructive airways disease and who had chronic stable angina pectoris. The study design involved a 20-week, placebo-controlled, double-blind, randomized cross-over trial, using acebutolol, an agent with partial agonist activity that has been shown to be effective in the treatment of hypertension, cardiac arrhythmias, and angina pectoris. Utilizing spirometry, flow volume loops, and arterial blood gas analyses, this study demonstrated that acebutolol had no significant deleterious effect on resting pulmonary function when used in clinically effective dosages.

Acebutolol↗
PubMed1981

Acebutolol and left ventricular function: assessment by radionuclide angiography.

We assessed the effects of acebutolol, a cardioselective beta blocker, on global and regional left ventricular function in 26 patients with chronic angina pectoris. All patients underwent rest and maximal supine bicycle exercise radionuclide angiography while on placebo and oral acebutolol (400 mg three times a day). Resting ejection fraction on placebo was 51 +/- 3% and on acebutolol was 54 +/- 3% (p less than 0.05). No resting ejection fraction decreased greater than or equal to 7%. Only one patient (resting ejection fraction 28% on placebo and 21% on acebutolol) developed signs of fluid retention. Exercise nuclear studies on placebo revealed responses consistent with coronary artery disease (abnormal ejection fraction response to exercise and regional wall motion abnormalities) in 24 of 26 patients. Peak exercise ejection fraction was of the same order on placebo and acebutolol (51 +/- 3% and 54 +/- 3%, p = NS). In four patients the ejection fraction response to exercise became normal and in five patients all regional wall motion abnormalities became normal on acebutolol. Cardioselective beta blockade with acebutolol in effective antianginal doses is safe and may improve resting and exercise ventricular function.

Acebutolol↗
PubMed1981

Comparative beta-blocking potencies of acebutolol and propranolol relative to plasma drug levels.

In a double-blind placebo cross-over study, the beta-blocking potencies of acebutolol and propranolol were compared in ten healthy subjects under steady-state conditions of oral drug administration. Beta-adrenergic blockade, determined by the degree of attenuation of tachycardia induced by standardized multistage treadmill exercise, was correlated with dose as well as with the plasma levels of the two beta antagonists. On a weight-for-weight basis, propranolol was about 4 times as potent as acebutolol in inhibiting exercise-induced tachycardia and in reducing the heart rate times systolic blood pressure product due to exercise. A weak correlation was demonstrated between the degree of beta blockade and plasma concentrations of propranolol (r = 0.381, p less than 0.01) or acebutolol (r = 0.333, p less than 0.001), there being up to 20-24 fold interindividual variation in plasma level for a given dose of each compound. Plasma acebutolol levels were associated with at least twofold greater levels of its acetyl homologue metabolite. A positive linear correlation was found between percentage beta blockade and the corresponding doses of propranolol (r = 0.503, p less than 0.001) and of acebutolol (r = 0.574, p less than 0.001). Our overall data provide little support for the use of plasma levels of acebutolol and propranolol as a guide to beta-blocking therapy with these compounds.

Acebutolol↗
PubMed1980

The long-term suppression of ventricular arrhythmia by oral acebutolol in patients with coronary artery disease.

The short-term efficacy of oral acebutolol was evaluated in 20 patients with coronary artery disease and frequent premature ventricular contractions (PVCs) by serial 24-hour Holter monitoring before and while the patients were receiving an average daily dose of 1,100 mg. of acebutolol for four weeks. Fifty-five percent of the 20 patients showed a greater than 70% PVC reduction from baseline values. The only serious side effect during short-term therapy was mild, reversible cardiac decompensation in one patient. The long-term safety and continued efficacy of acebutolol was then evaluated over the next 11 months in nine of the 11 patients showing greater than 70% PVC reduction at four weeks. Two-thirds of these nine patients continued to show greater than 80% PVC reduction from baseline values at 12 months. One patient developed alopecia during long-term therapy. The majority of patients not responding well to acebutolol at four weeks had an actual increase in PVCs on acebutolol therapy. We conclude that acebutolol produces long-term, effective reduction in PVCs without serious toxicity in the majority of patients with ventricular ectopy. However, this drug appears to either produce an excellent response or no response with regard to PVC control in most instances.

Acebutolol↗
PubMed1975

Myocardial distribution of coronary blood flow in the isolated supported heart preparation.

The regional distribution of myocardial blood flow was studied by use of radioactive microspheres (15 micro-meters [mum]) under control conditions and during an intracoronary infusion of norepinephrine (2mug/min). In control experiments endocardial blood flow was generally greater than epicardial flow; during administration of norepinephrine the endocardium received significantly less blood flow. It is proposed that normally the endocardium is well perfused, but under conditions of stress, eg, norepinephrine infusion in the presence of a constant coronary blood flow, decreased endocardial blood flow results.

Animals↗